CVE-2023-27351
HIGH KEV RANSOMWARE NUCLEIPaperCut MF and NG 15.0.0-20.1.6 and 22.0.5 - Unauthenticated Authentication Bypass in SecurityRequestFilter
Title source: llmExploitation Summary
CVE-2023-27351 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added April 20, 2026, with confirmed use in ransomware campaigns. A Nuclei detection template is also available.
Description
This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.
Nuclei Templates (1)
PaperCut NG - Authentication Bypass
HIGHVERIFIEDby daffainfo,jjcho
Shodan:
http.html:"PaperCut" || http.html:"papercut" || http.html:"content=\"papercut\"" || cpe:"cpe:2.3:a:papercut:papercut_mf"
FOFA:
body="papercut" || body="content=\"papercut\""
References (3)
Core 3
Core References
Vendor Advisory
https://www.papercut.com/kb/Main/PO-1216-and-PO-1219
Third Party Advisory, VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-23-232/
Third Party Advisory, US Government Resource
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27351
Scores
CVSS v3
7.5
EPSS
0.6564
EPSS Percentile
98.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA SSVC
Vulnrichment
Exploitation
active
Automatable
yes
Technical Impact
total
Details
CISA KEV
2026-04-20
VulnCheck KEV
2023-04-28
ENISA EUVD
EUVD-2023-31127
Ransomware Use
Confirmed
CWE
CWE-287
Status
published
Products (3)
PaperCut/NG
22.0.5 (Build 63914)
papercut/papercut_mf
15.0.0 - 20.1.7
papercut/papercut_ng
15.0.0 - 20.1.7
Published
Apr 20, 2023
KEV Added
Apr 20, 2026
Tracked Since
Feb 18, 2026